Coal mining machine with eccentrically mounted disk cutters



J. S. ROBBINS Sept. 29, 1953 COAL. MINING MACHINE WITH ECCENTRICALLY MOUNTED DISK CUTTERS Filed Feb. 1, 1949 INVENTOR: JAMES s. ROBBINS BY ATT'YS Patented Sept. 29, 1953 COAL MINING MACHINE WITH ECCENTRI- CALLY MOUNTED DISK CUTTERS James S. Robbins, Highland Park, Ill., assignor to Goodman Manufacturing Company, Chicago, 111., a corporation of Illinois Application February 1, 1949, Serial No. 73,948

3 Claims.

This invention relates to rock cutting machines, such as are used for driving tunnels into veins of coal and other frangible rock material and has particular reference to improvements in the rock cutting and breaking devices for such machines.

The main objects of this invention are to provide cutters of improved form and. arrangement for cutting parallel kerfs in the face of the rock and then breaking down the ribs that are formed between such kerfs; to provide an improved arrangement of the cutting devices in such machines, whereby the fragments of rock resulting from the cutting operation are handled in an improved manner so as to prevent accumulation thereof from clogging or otherwise interfering with the continuous operation of the cutters; to provide an improved form and arrangement of the rock breaking devices with respect to the cutting tools, whereby the breaking operation will occur intermittently during the continuous operation of the cutters, so that the tendency of the cutters to provide pulverized material will be reduced to a minimum and the material will be delivered with a larger proportion of the large fragments; to provide an improved arrangement of cutters whereby they will cut a tunnel of rectangular cross section With a minimum of manual or supplemental trimming operations; and to provide such improved machines capable of continuous forward progress during the cutting operations.

A specific embodiment of this invention is disclosed in the accompanying drawings with the form and location of the cutting devices shown in detail and with the framework and operating mechanism of the machines indicated schematically.

Figure 1 is a partly sectional side elevation, somewhat schematic, of a coal mining machine constructed according to this invention, the sectional portions are taken on the line ll of Fig. 2.

Fig. 2 is a sectional detail of the same, the section being taken on the line 2-2 of Fig. 1.

Fig. 3 is a diagrammatic detail showing an arrangement of driving mechanism suitable for operation of the cutters of such machine.

In the form shown in the drawings, the main cutter-carrying shafts are journaled side by side with their axes vertical and parallel and spaced apart horizontally. The main shafts 29 are mounted at the front end of the machine and substantially parallel to the rock face at the end of the tunnel that is out by the machine. The plane defined by these shafts is indicated by line A-A in each of Figs. 1, 2 and 3.

The cutters 2| are in the form of disks having thin marginal portions 22 with teeth 23 on their peripheries and with conical shoulders 24 on their body portions 25. These cutting disks are axially spaced at uniform intervals along their respective shafts 20 and arranged to rotate freely on circular eccentrics 26 which are fast on said shafts.

The crank arms of the eccentrics on each shaft 20 are disposed in angularly staggered relation to each other and the cutters 2| on each shaft are arranged in mating pairs with those on the other shaft for cutting alined kerfs in a rock face. The arrangement is preferably such that the kerf cut by each cutter on one main shaft will lie in the same plane of and merge with the kerf cut by the mating cutter on the other shaft. The overlapping circular paths of such pairs of mating cutters with respect to the shafts 20 are indicated in Fig. 2 partly by a representation of the rock face at the bottom of the kerfs and partly by the broken lines 26.1.

The cutting disks 2| are journalled to turn freely about the axes of their respective eccentries 26, but their bodily movement is such that a considerable depth of kerf is cut by the marginal portions 22 of each of the disks 2| before the wedging effect of its body portion 25 breaks down the ribs of rock standing between the kerfs. The disks 2| should each have an odd number of cutting teeth around its periphery to produce the best cutting effect, as the cutting is accomplished by chisel-like penetration of the teeth as the cutters roll on the rock face.

The supporting frame in which the cutter shafts 20 are journalled is indicated schematically by the framework 21 at the front end of the tractor body or chassis. Each shaft 20 has fixed thereon a sprocket 28 driven by a chain belt 29 and a driving sprocket 30 of the operating mechanism which is shown schematically in Figs. 1 and 3. As diagrammatically indicated in Fig. 3, the shafts of the sprockets 30 are connected by intermeshing gears 3| driven by a worm 32 meshing with a worm wheel 33 and driven by a motor 34.

In the form shown, the main shafts 20 are rotated in opposite directions so that the cutters 2| of one shaft travel toward those of the other at the front of the machine, thus carrying the cuttings toward the center line of the path of travel of the machine, where they are scooped up and carried away by conveyor 35.

Since the cutters are carried bodily in circular paths about the main shafts and are journalled to rotate freely on the minor axes of the eccentries, the cutters have a rolling motion through frictional contact with the rock as they are forced to travel bodily about the main shafts 20 by their eccentrics 26. Their teeth are pressed into the rock face by the forward action of the machine, so as to crush the rock by a chisel-like action of the teeth. On certain kinds of coal and other materials, the free rolling cutters may be devoid of teeth on their peripheries. The mating cutters on the two main shafts travel overlapping paths, and the eccentrics on the shafts are disposed so as to prevent interference between the mating cutters; for example, the eccentrics on one shaft 20 may be angularly disposed 180 apart from those on the other shaft 20, as mdicated in Figs. 2 and 3.

In general arrangement the cutters are arranged in banks about their main driving shafts. being distributed throughout the length of such shafts so that the paths of the cutters conform to a bank of substantially uniformly spaced parallel kerfs defining a rock wall area of the same form and dimensions as the cross section of the tunnel. This enables the machine to progress forward continuously at a substantially uniform speed of travel. This arrangement of cutters greatly simplifies the structure of the machine and its operating mechanism by eliminating many operations that are incidental to prior existing forms of tunnel cutting machines.

It will be understood that the structure shown and described may be modified by alteration or omission of details without departing from the spirit of the invention as defined by the following claims.

I claim:

1. In a machine of the class described, a power driven shaft, an eccentric fixed on said shaft, a cutter disk mounted to rotate freely about the axis of said eccentric and comprising an annular series of teeth and a tapered annular shoulder spaced inward from and concentric with said series of teeth so as to follow the teeth into a kerf cut thereby and wedgingly bear on one side of such kerf.

2. A mining machine, comprising a portable frame mounted to travel forward against a rock wall, a pair of driven shafts journalled on said frame and spaced apart in parallel relation to each other in a plane transverse to the path of forward travel of said frame, each of said shafts having fixed thereon a series of axially spaced eccentrics having their axes distributed angularly about the axis of the respective said shaft, 9. series of cutters each journalled to rotate freely on its respective one of said eccentrics, said shafts being spaced apart and having their cutters located in relatively mated sets so that the paths of the cutters on one said shaft will overlap the paths of rnating cutters on the other said shaft, and driving means operatively connected to said shafts for simultaneously rotating said shafts, each said cutter comprising a disk having an annular series of teeth concentric with the axis of its respective eccentric and having an annular body wedgeshaped in radial section and positioned to enter a kerf cut by its said teeth in the rock wall to break the rock at one side of such kerf.

3. A mining machine, comprising a portable frame, means connected to and coacting with said frame to drive it forward against a rock wall, a shaft journalled on said frame on an axis substantially parallel with said rock wall, a series of like axially spaced eccentrics on said shaft, cutters journalled to rotate freely on said eccentrics, and means for rotating said shaft and applying power thereto at leverage greater than that of said eccentrics, each said cutter comprising a circular disk having a thin marginal rim and an annular wedge-shaped body portion located concentrically inwardly from said rim and tapered conically away from the plane of said rim in position to enter a kerf cut by said rim and break down the rock at one side of such kerf.

JAMES S. ROBBINS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 970,725 Kuhn Sept. 20, 1910 981,201 Kuhn Jan. 10, 1911 1,116,355 Morgan Nov. 3, 1914 1,791,865 Fordyce Feb. 10, 1931 2,404,605 Thompson July 23, 1946 

